Compatibility of household appliances with DC microgrid for PV systems

Abstract

DC distribution of PV systems has spread back especially in the residential sector as a variety of electronic appliances became locally available in the market. The compatibility of household appliances with the best voltage-level in a DC environment is the field that still in the research phase and has not yet made a practically extensive appearance. This paper mainly discusses this issue by providing a review of the concerning research efforts, identifying the gaps in the existing knowledge. The work explains the electrical diagrams of the recently produced appliances, classifying them to get an understanding of how each one consumes energy. It includes exploiting the recent dependence of the commercial appliances on power electronics to improve the efficiency of the existing DC distribution systems by extrapolating new architectures. The proposed topology has a DC distribution environment with two levels of voltage for all appliances. Appliances performances have been evaluated by calculating the energy transfer efficiency. The outcomes of this work can help in designing more efficient DC power distribution networks with minimal energy converters and establishing standardizations for DC microgrids.

Design and Control of a Battery Charger/Discharger Based on the Flyback Topology

“…, which is replaced into the averaged model (12) to obtain the closed-loop dynamics of the bus voltage under the action of the SMC:…”

“…The first step of the design process is to define the design requirements. Table 1 reports the requirements adopted for illustrating the design process, where a standard 12 [V] volt battery must be connected to a 48 [V] bus, which is used in DC microgrids [10][11][12]. The battery charger/discharger must be designed to provide or absorb a maximum of 1 [A], with a maximum slew-rate (current derivative) of 50 [A/ms], which could completely charge (SOC = 100%) a EnerSys NP0.8-12-ND [41] lead-acid battery (12 V-0.8 Ah) in 48 min, or charge/discharge the 10% of the SOC in 4.8 min.…”

“…The DC bus voltage (v dc ) is usually greater than the battery voltage (v b ); hence, bidirectional step-up converters like Boost [2][3][4] or Buck-Boost [5,6] are commonly used. Considering that these converters have limited voltage gains, a typical value of v b is 12 V [7][8][9], and the values of v dc in microgrid applications vary in wide range, but are significantly greater than v b (e.g., 48 V [10][11][12], 200 V [13]), or higher [14]; then, multiple batteries are connected in series and parallel to reach the required voltage and storage capacity levels, respectively. Those batteries have different electrical characteristics due to manufacturing imperfections, uniform aging, and continuous charging/discharging cycles; these differences produce excessive heat and accelerated degradation of the batteries [15].…”

Adoption Pathways for DC Power Distribution in Buildings

“…DC has been available in telecommunications and certain niche markets (e.g., recreational vehicles, off-grid systems, marine applications) for decades. However, despite the gradual shift to more efficient DC-internal devices in grid-connected building applications (electronics, solid-state lighting, brushless DC motors, and/or variable frequency drives), most electrical end uses in buildings today have an AC power input and include a rectifier, or power supply, to convert AC to DC [3], [30], [31]. In this paper, we group DC EUDs into the following categories: lighting, electronics, motor-driven equipment, and other miscellaneous equipment, the latter encompassing EUDs not included under the first three categories, such as resistive loads.…”

A general study of designing an electromagnetic induction cooking device prototype for microgrids in rural areas

“…Promoting renewable energy usage such as DC microgrid systems in rural areas to cover the demand for electricity consumption that the conventional electricity grid cannot supply is one of the objectives to attain over the last years [1,2]. Therefore, the development of devices with a minimum power consumption required for domestic appliances compatible with these systems is sought [3]. In this context, using electromagnetic induction cooking devices for microgrids is an alternative for users to reduce the consumption of traditional stoves (e.g., wood-based or charcoal-based stoves), which emit harmful gases in enclosed spaces to the population over time [4].…”